HIGH-T(C) SUPERCONDUCTOR POLYMER COMPOSITES - MODELING OF ABNORMAL ELECTRICAL-PROPERTIES AT LOW-TEMPERATURE

High-T(c) 2223-bismuth superconducting pigments have been inserted in a matrix of Fe3+ -doped polyphenylene sulphide (PPS) to obtain new com posites with variable properties. The fabrication and the characteriza tion of the various components are briefly described. The electrical r esistivity at a low temperature of the composites is reported. In the case of multiphase superconducting pigments presenting various T(c)'s and semiconducting fabrication residues inserted in the polymeric matr ix, the composites are characterized by abnormal resistivity evolution s between 20 K and 300 K. A new electrical model is proposed to interp ret the behavior of such composites in the full 5 K to 300 K temperatu re range. Percolation features are taken into account through an empir ical description of the electrical complex impedances. The computer ca lculations allow one to characterize fabrication residues and interfac es between insulating, conducting and superconducting areas in the com posites.